1. Field of the Invention
The present invention relates to apparatus for stacking and conveying container lids, and more particularly to an assembly for the transfer of the lids from a horizontal, spaced apart position on a moving conveyor belt, to an upright vertical spinning position.
2. Description of the Prior Art
The manufacture of lids for disposable as well as reusable containers designed for a variety of packaging needs, generally includes the conveyance of the container lids through a sequence of operations, including printing on one surface thereof of various commercial indicia. Generally, the container lids are introduced on to a horizontal conveyor where they reside in spaced apart position, where printing or other operations may be performed on them.
A variety of conveyor apparatus has been developed and utilized to transport and stack container lids of various sizes and utilities. Such apparatus operate continuously, and achieve commercial speeds of about 300 lids per minute. Generally, such apparatus includes an output section where the container lids are transferred from the horizontal conveyor to a vertical, rotating stacked arrangement, where they may be transferred or otherwise prepared for shipment. One particular type of lid conveying apparatus utilizes the principle of gyroscopic precession, as outlined in U.S. Pat. No. 3,463,293, to Lederer, to stack the lids on their rims, and maintain the lids closely adjacent and axially aligned with each other in motion, to facilitate such transport and packaging.
Generally, the output end of such apparatus includes a device such as a chute or the like, that facilitates the movement of the generally horizontal container lids into the vertical plane for reception by the spinning rods. A particular such device, including a lid orienting mechanism is disclosed in U.S. Pat. No. 3,311,218, also to Lederer. The mechanism of this patent is specifically designed to facilitate the orientation of the container lid so that lids that have been oppositely disposed on the horizontal conveyor, may nonetheless be converted to the proper vertical alignment on the spinning rods. The Lederer device provides a direct vertical chute that may terminate at the spinning rod stacking device.
One of the problems that attends the use of the chute in conjunction with the spinning rod arrangement, is that container lids occasionally misfeed from the chute and either disrupt the vertical stack on the spinning rods, or are totally ejected from such stack. Ejection may occur because of the manner in which the spinning rods operate. Specifically, both rods spin in the same direction, for the purpose of imparting a tangential, gyroscopic spin of opposite direction to the container lids, to keep the lids stable in the vertical position as illustrated in the Lederer Patent. It can be seen, that the initial contact of a container lid with one, rather than both of the spinning rods, could cause that container lid to eject from the apparatus.
A further difficulty with the use of the vertical chute in conjunction with the spinning rods, arises from the occasional instability of container lids initially contacting the spinning rods, due to inadequate preliminary preparation or "prespinning" of the container lids. Generally, because of the forces exerted by the spinning rods, it is advisable to prepare the container lids by imparting some complementary rotation to them as they move toward the rods. This generally facilitates the assumption by the container lids of a stable residence on the rods, which in turn lends stability to the spinning stack. Prior art mechanisms for imparting such spinning have been generally inadequate, and, at most, consist of free wheeling rollers disposed adjacent the mouth of the vertical chute, to cause passing container lids to assume some initial rotation in their movement. Such rotation is generally inadequate, and the container lids may wobble and cause instability to the remainder of the stack.
This latter problem is compounded, by the design of the conventional chute, as the container lids are usually dropped directly vertically downward, and thereby may land in contact with the next adjacent rotating container lid. This manner of delivery can cause instabilities and disruption, in the instance where a container lid unexpectedly accelerates and drops to the spinning rods, before the previous lid can move out of the way.
A need therefore exists for the development of a means for transferring the container lids from the horizontal conveyor to the vertical spinning rods at the high speeds of commercial operation, with minimum operating disruption.